In recent years, a PON (Passive Optical Network) system has become employed in an access system network that links homes, companies, and the like with an upper network. The PON is a communication system having a configuration in which a master station device (OLT: Optical Line Terminal) and a plurality of slave station devices (ONU: Optical Network Unit) are connected in one-to-many relationship with an optical fiber and a splitter.
For example, the PON system includes an EPON (Ethernet® PON) system defined in Non Patent Literature 1. In the EPON system, the data transmission rate of the upstream and downstream communications is set to 1 Gbit/s, and a bidirectional communication is performed by the wavelength division multiplexing method using different wavelengths for the upstream communication and the downstream communication. When the ONU transmits upstream data, the data is transmitted by the time-division multiplexing method in which a plurality of ONUs use an upstream bandwidth in a divided manner.
Furthermore, in the EPON system, setting a management channel for each logical link is defined in Non Patent Literature 1, while data transmission is controlled for each logical link. The management channel is a channel that is used for performing management of a logical link and management of a device (management of a slave station device), and in the management of the device, for example, acquisition and notification of a device management status, device setting, and the like are performed. In the control using the management channel, control data is transmitted and received by using an OAM (Operation, Administration, Maintenance) frame.